JP2000161375A - Rotary main spindle cooling structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain sufficient cooling efficiency by jetting a cooling air within a specified angle range toward a specified portion or a plurality of specified portions of a gap communicating a plurality of ball bearings with each other between an outside fixing body and an inside rotating body. SOLUTION: A rotating face of an inside rotating body 1 is determined for a reference and a cooling air is jetted to one portion or a plurality of portions of a gap 3 located between an outside fixing body 2 and an inside rotating body 1 at an angle of -45 deg. to +45 deg. in a rotating direction of the inside rotating body 1. As a result, in both cases of a case where cooling air collides against an outside surface of the inside rotating body 1 or a case where cooling air collides against an inside surface of the outside fixing body 2, components of cooling air moving in the direction opposite to the rotating direction of the inside rotating body 1 becomes a remarkably little amount and relatively large amount of cooling air moves in the same direction together with a rotating ball 41 along the rotating direction of the inside rotating body 1. Therefore, cooling air circulates in the gap 3 for a long time without decreasing wind speed, thus a cooling effect can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling structure for a rotating spindle using a ball bearing in a machine tool or the like.

[0002]

2. Description of the Related Art In a rotary spindle for high-speed rotation, lubrication and cooling are simultaneously realized by an oil-air system, or cooling is performed by irradiating a bearing with cold air adiabatically expanded by a cold air low-pressure blowing system. Have been.

[0003] In each of the above methods, as shown in Figs. 1 (a) and 1 (b), at the substantially central position or end portion of the rotating main shaft in the axial direction, the rotating center of the inner rotating body 1 is rotated. Oil oil or cooled air is ejected in the direction, and the air that has passed through the cooling process is discharged to the inner rotating body 1.
The water is discharged to the outside through an end portion between the outer fixed body 2 and the outer fixed body 2 or a hole provided particularly in the outer fixed body 2. During the jetting, the air pressure between the inner rotating body 1 and the outer fixed body 2 is a low pressure of about 0.02 kgf / cm ² ,
It does not mean that it is in a so-called high-pressure compression state.

However, when the cool air is blown in the direction toward the center of rotation, if it is considered on the basis of the rotating surface, it is blown as shown in the attached drawing 2 and the inner rotating body 1
About half of the cold air that has collided with the inner rotator 1 moves along the rotation direction of the inner rotator 1, but the other half must move in the opposite direction to the rotation direction of the inner rotator 1.

[0005] The cool air moving in the direction opposite to the rotation direction of the inner rotating body 1 collides with the rotating ball 41 of the ball bearing 4 and its speed is rapidly reduced, so that the cooling time is inevitably shortened. However, the cooling efficiency must be reduced.

That is, in the conventional cooling method of the rotating main shaft, since the injection angle of the cool air in the rotation direction plane of the inner rotating body 1 is not particularly taken into consideration, the cool air moving in the opposite direction to the rotation direction as described above is removed. And the disadvantage that sufficient cooling efficiency cannot be obtained.

[0007]

SUMMARY OF THE INVENTION The present invention focuses on the problems of the prior art described above, and the cold air injected into the gap between the inner rotating body and the outer fixed body is opposite to the rotating direction of the inner rotating body. It is an object of the present invention to provide a configuration in which there is no portion moving in the direction or the amount of movement in the opposite direction is reduced.

[0008]

In order to solve the above-mentioned problems, the present invention provides a construction in which one or more of a plurality of ball bearings are provided between an outer fixed body and an inner rotating body in a space communicating with each other. For a specific part of the place, cool air,
The cooling structure of the rotating main shaft is formed by jetting the gas in the angle range of −45 ° to + 45 ° with respect to the rotation direction of the inner rotating body at the specific portion with respect to the rotating surface of the inner rotating body.

[0009]

According to the present invention, as shown in FIGS. 3 (a) and 3 (b), when the rotating surface of the inner rotating body 1 is used as a reference, cool air is blown between the outer stationary body 2 and the inner rotating body 1. At a position or a plurality of positions of the gap 3 located at the position −45 ° to + 45 ° with respect to the rotation direction of the inner rotating body 1 at the position.
It has a basic feature in that it is injected at an angle of °.

FIG. 3A shows a case where the angle direction is about + 30 ° out of the above-mentioned angle range.
It collides with the surface and then moves in the gap 3.

On the other hand, FIG. 3B shows a case where the angle is an angle direction of -30 °. In this case, the injected hot air collides with the inner surface of the outer rotating body. And
After that, it moves in the gap 3.

The reason why such an angle range is set is that, in the prior art, as shown in FIG. 2, about half of the injected cold air moves in the direction opposite to the rotation direction of the ball bearing 4 and the rotating ball 41 is rotated. This is to avoid a rapid deceleration due to collision with the vehicle, and thus a decrease in the efficiency of the cool air. That is, when the cool air is injected in the above angle range with respect to the rotation surface of the inner rotating body 1, FIG.
3A, the cold air collides with the outer surface of the inner rotating body 1, or the cold air collides with the inner surface of the outer fixed body 2 as shown in FIG. The component of the cold air moving in the direction opposite to the rotation direction of the inner rotating body 1 is a considerably small amount, and can avoid the drawbacks of the prior art.

With reference to the plane in the direction of the rotation axis, in the prior art, the cool air is blown in the direction perpendicular to the rotation axis. In the present invention, however, the cold air is blown in the plane direction perpendicular to the rotation axis. This is not always necessary (in short, it is only necessary to satisfy the requirements regarding the angle).

However, when the rotating balls 41 or the ball bearings 4 are present on both sides, it is convenient to inject in a direction perpendicular to the rotating axis, as in the case of the prior art, with reference to the surface in the rotating axis direction. On the other hand, ball bearing 4
Alternatively, when the rotating ball 41 exists only on one side, it is also possible to select to inject the cold air in a direction toward the one side instead of a direction orthogonal to the rotating axis with respect to the direction surface of the rotating shaft.

As described above, in the configuration of the present invention, when the rotating surface of the inner rotating body 1 is used as a reference, a relatively large amount of cool air is generated along the rotating direction of the rotating ball 41 along the rotating direction of the inner rotating body 1.
And the same direction, the wind speed does not decline and the air gap 3 between the outer fixed body 2 and the inner rotating body 1 is circulated for a long time, whereby the cooling effect can be improved. In the present invention, the inner rotating body 1 is also used.
The air pressure between the outer fixed body 2 and
It does not mean that it is in a high pressure state by so-called compressed air.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, as shown in FIG. 4, when the fuel is injected at an angle of 0.degree. With respect to the rotation direction of the inner rotating body 1, the inner rotating body 1 or the outer fixed body 2 is theoretically connected to the inner rotating body 1. The reflected cold air does not exist due to the collision, and most of the cold air actually moves in the same rotation direction as the ball bearing 4.

In this embodiment, the angle range of -45 ° to + 45 ° is 0 ° as the most preferred embodiment.

With this configuration, a more efficient cooling effect can be obtained.

[0019]

FIG. 5 shows the cooling structure employing the conventional oil-air method and the injection in the present invention when the same cold air is blown to the main shaft of the outer fixed body and the inner rotating body of the same design. It is the graph which compared the degree of temperature rise at the time of increasing rotation speed sequentially about the cooling structure which injected at an angle of +45 degrees with respect to the rotation direction of the inner rotating body of a position.

As is apparent from FIG. 5, compared with the conventional oil-air system, the configuration according to the present invention has a very low temperature rise even if the injection is performed at the 45 ° angle as described above. Turns out.

As described above, according to the present invention, by devising the injection angle of the cool air, more efficient cooling can be realized as compared with the prior art, and the value of the present invention is enormous.

[Brief description of the drawings]

FIG. 1 is an axial cross-sectional view showing a cooling structure according to a conventional technique, where (a) shows an oil-air system and (b)
Indicates a cold air low pressure air blowing system.

FIG. 2 is a cross-sectional view in the rotation direction showing that, in the related art, when cool air is injected to the surface of an inner rotating body, a considerable portion of the cool air moves in a direction opposite to a rotation direction of a bearing.

FIG. 3 is a sectional view in the rotation direction showing the configuration of the present invention;
(A) shows a case where the injected cool air collides with the outer surface of the inner rotating body, and (b) shows a case where the injected cool air collides with the inner surface of the outer fixed body ( still,
Arrows indicate the direction of rotation of the inner rotating body. ).

FIG. 4 is a sectional view in the rotational direction showing the configuration of the embodiment.

FIG. 5 is a graph for comparing the degree of temperature rise in both the conventional structure using the oil-air system and the structure in which the injection is performed at an angle of 45 ° with respect to the rotation direction of the inner rotating body in the present invention. It is a graph.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 inner rotating body 2 outer fixed body 3 air gap 4 ball bearing 41 rotating ball 5 cool air injection pipe 6 flow direction of cool air

Claims (2)

[Claims] 1. A method according to claim 1, wherein a plurality of ball bearings are interconnected between the outer fixed body and the inner rotating body. The cooling structure of the rotating main shaft by jetting in an angle range of -45 ° to + 45 ° with respect to the rotating direction of the inner rotating body with respect to the rotating direction. 2. An angle of 0 ° with respect to a rotation plane of the inner rotating body.
2. The cooling structure for a rotating main shaft according to claim 1, wherein the fuel is ejected at an angle of.